This invention relates to a replaceable wear plate for installation in a railway car center sill to protect the upper bearing surface of each of the draft key slots.
In a railroad car a coupler and its associated yoke are secured at each end of the car to a center sill casting by a horizontal draft key. The key passes through key slots in the coupler shank and yoke hood, and the outer ends of the key are confined within a horizontal key slot in each of the center sill side walls.
The weight of the coupler extending outwardly from the sill tends to raise the butt end of the coupler shank, thereby raising the draft key until it contacts the upper bearing surface of each of the sill key slots.
When cars are coupled together and the train is in motion, the cars have a tendency to "run-in" and "run-out" (i.e., move longitudinally toward and away from each other), which causes the couplers to move inwardly and outwardly. When the draft key is in contact with the upper bearing surface of the sill key slots and the cars are moving, the key rubs against the upper bearing surface causing it to wear. The bottom bearing surface, which is also contacted by the key, experiences little, if any, wear and has not presented a wear problem.
In order to repair a worn upper bearing surface, the car must be taken out of service, and depending upon the condition of the sill, either the entire sill is replaced or the worn area is repaired by welding, which is both costly and time-consuming.
It is, therefore, an object of this invention to substantially prevent or reduce wear of the upper bearing surface of the sill key slots in order to minimize the cost and frequency of repairing the center sill.
This and other objects of this invention will become apparent from the following description and appended claims.